The same group that claimed responsibility for an attack on a Kenyan mall this weekend that has claimed at least 62 lives has previously recruited dozens of Americans to join their cause.

U.S. officials estimate that as many as 50 Americans have traveled to training camps in Somalia, the home of the al Qaeda-linked terror group al-Shabaab, over the last six years.

Just last month, al-Shabaab released a video showing three young men claiming to be from Minneapolis who the terror group said later died as martyrs.

"This is the best place to be honestly," one of the men says. "I can only tell you from my experience being here, that you have the best of dreams, you eat the best of food, and you're with the best of the brothers and sisters who came here for the sake of Allah. If you guys only knew how much fun we have over here. This is the real Disneyland, you need to come here and join us and take pleasure in this fun."

Another American, Omar Hammami of Daphne, Ala., rose to a leadership position in al-Shabaab until he was reportedly killed by rivals in the group earlier this month. Hammami, widely known as the rapping jihadist, recorded several videos of himself rhyming about what he saw as his holy war against the West and the glory of martyrdom.

Hammami and other al-Shabaab leaders have vowed to hit U.S. targets and officials worry the American recruits still there could return home with that mission in mind.

"This is something scary," Ali Soufan, a former FBI agent and terror expert, told ABC News. "I mean, if you think about individuals who went and fought in a place like Somalia and when they come back home, there's nothing good that can come of this... What we see today in Kenya could be easily copied here in the United States."

Earlier this month ABC News reported that intelligence and law enforcement officials said at any given moment, the FBI has under watch as many as 100 people in the U.S. suspected of being linked to or inspired by al Qaeda or its affiliates.

During Congressional testimony in January 2012, Director of National Intelligence James Clapper listed al-Shabaab as one of the most significant terror threats to the homeland, in part due to a "foreign fighter cadre that includes U.S. passport holders... [who] may have aspirations to attack inside the United States."

However, a senior law enforcement official said the latest U.S. government analysis shows no heightened threat to the U.S. as a result of the Kenya attack. While al-Shabaab does have a desire to strike at Western targets in Africa, hitting the U.S. homeland is "not a priority" for them, the official said.

Al-Shabaab claimed the attack on the Westgate Mall in Kenya was retaliation for the 2011 invovlement of Kenyan forces in anti-terror operations in Somalia.

ABC News' Dana Hughes and Mike Levine contributed to this report.

[Editor's Note: A previous version of this report put the death toll at 68. The figure cited above reflects the most recent count by the Kenyan Interior Ministry provided Monday morning.]